<!DOCTYPE html>
<html>
<!--
Copyright 2014 The Closure Library Authors. All Rights Reserved.

Use of this source code is governed by the Apache License, Version 2.0.
See the COPYING file for details.
-->
<head>
<title>goog.events.WheelHandler</title>
<link rel="stylesheet" href="../css/checkbox.css">
<style>
#out {
  background-color: #eee;
  width: 500px;
  height: 500px;
  position: relative;
  display: inline-block;
}

#h-line, #v-line {
  position: absolute;
  background: black;
}

#h-line {
  width: 20px;
  height: 1px;
}

#v-line {
  width: 1px;
  height: 20px;
}

#status {
  position: absolute;
  bottom: 0;
  right: 0;
  font: 70% sans-serif;
}

#debug {
  font-family: monospace;
  white-space: pre;
  display: inline-block;
}

</style>
<script src="../base.js"></script>
<script>

goog.require('goog.events');
goog.require('goog.events.WheelHandler');

</script>
</head>
<body>

<h1>goog.events.WheelHandler</h1>

<p>Use your mousewheel on the gray box below to move the cross hair.

<div id=out>
  <div id=h-line></div>
  <div id=v-line></div>
  <div id=status></div>
</div>

<div id=debug>
</div>

<script>

var WheelHandler = goog.events.WheelHandler;
var WHEEL = WheelHandler.EventType.WHEEL;

function $(id) {
  return document.getElementById(id)
}

var x = 250, y = 250;
var out = $('out');
var hLine= $('h-line');
var vLine = $('v-line');
var statusLine = $('status');
var debug = $('debug');

var availWidth = out.clientWidth - vLine.offsetWidth;
var availHeight = out.clientHeight - hLine.offsetHeight;

function handleWheel(e) {
  x += e.pixelDeltaX;
  x = Math.max(0, Math.min(availWidth, x));
  y += e.pixelDeltaY;
  y = Math.max(0, Math.min(availHeight, y));
  updateLines();
  e.preventDefault();
  var deltaModeString = 'unknown';
  var DeltaMode = goog.events.WheelHandler.DeltaMode;
  switch (e.deltaMode) {
    case DeltaMode.PIXEL:
      deltaModeString = 'DeltaMode.PIXEL';
      break;
    case DeltaMode.LINE:
      deltaModeString = 'DeltaMode.LINE';
      break;
    case DeltaMode.PAGE:
      deltaModeString = 'DeltaMode.PAGE';
      break;
  }
  var debugObject = {
    type: e.type,
    deltaMode: deltaModeString,
    deltaX: e.deltaX,
    deltaY: e.deltaY,
    deltaZ: e.deltaZ,
    pixelDeltaX: e.pixelDeltaX,
    pixelDeltaY: e.pixelDeltaY,
    pixelDeltaZ: e.pixelDeltaZ,
  };
  debug.innerText = JSON.stringify(debugObject, undefined, 4);
}

function updateLines() {
  vLine.style.left = x + 'px';
  hLine.style.left = x - hLine.offsetWidth / 2 + 'px';
  hLine.style.top = y + 'px';
  vLine.style.top = y - vLine.offsetHeight / 2 + 'px';
  statusLine.innerText = x + ', ' + y;
}

updateLines();

var mwh = new WheelHandler(out);
goog.events.listen(mwh, WHEEL, handleWheel);

goog.events.listen(window, 'unload', function(e) {
  goog.events.unlisten(mwh, WHEEL, handleWheel);
});

</script>
</body>
</html>
